The MATCH() function is returning a value that will inform which row the hlookup will return a value from. In this case MATCH("Grand Total",All!A:A,0) is returning 36 but there are only 12 rows in your hlookup array as defined by All!7:18. With this in mind, try the following:

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=HLOOKUP(TEXT(B35,"mmm"),All!7:18,MATCH("Grand Total",All!A7:A18,0),FALSE)